thropocentric values. Acceptance of this leads to rights and interests-based arguments on behalf of
non-human nature. The existence of such philo- sophical views is one reason why the concept of
TEV should not be confused with the ‘total value’ of a wetland. Moreover, the social value of an
ecosystem may not be equivalent to the aggregate private TEV of that same system’s components;
the system is likely to be more than just the aggregation of its individual parts. See Gren et al.
1994 and Turner et al. 1997 on the existence of a ‘primary value’ of ecosystems.
The adoption of a functional perspective is the correct way to identify wetland goods and ser-
vices, but if each of them is identified separately, and then attributed to underlying functions, there
is a likelihood that benefits will be double counted. Benefits might therefore have to be allo-
cated explicitly between functions. For instance, Barbier 1994 noted that if the nutrient retention
function is integral to the maintenance of biodi- versity, then if both functions are valued sepa-
rately and aggregated, this would double count the nutrient retention which is already ‘captured’
in the biodiversity value. Some functions might also be incompatible, such as water extraction and
groundwater recharge, so that combining these values would overestimate the feasible benefits to
be derived from the wetland. Studies that attempt to value the wetland as a whole based on an
aggregation of separate values tend to include a certain number of functions although these stud-
ies do not usually claim to encompass all possible benefits associated with the wetland. Examples
include Thibodeau and Ostro 1981, Bishop et al. 1987, Costanza et al. 1989, Dixon 1989,
Hanemann et al. 1991, Hanley and Craig 1991, Loomis et al. 1991, Thomas et al. 1991, White-
head
and Blomquist
1991, Farber
1992, Ruitenbeek 1992, and de Groot 1994.
4. Stakeholders in wetland functions and values
Integrated ecological-economic
analysis in-
volves an identification of how particular func- tions might be of use, rather than simply the
degree to which the function is being performed. The extent of demand for the products or services
provided, or the effective ‘market’, also needs to be assessed if the full extent of economic value is
to be assessed. So who are the relevant users, i.e. those who assign economic values to wetlands? It
is possible to identify at least nine more or less organised groups of stakeholders:
1. Direct extensi6e users directly harvest wetland goods in a sustainable way, i.e. consistent with
rapid ecosystem recovery. They thus possess a particular form of ecological knowledge en-
abled by an institutional setting that may be under increasing environmental change pres-
sure. They harvest the wood for timber or fuel, the reed for roofs, the available wetland plants
and fruits for produce, the waterfowl and mammals for pelts and meat, and fishes and
shellfishes for food.
2. Direct intensi6e users have access to new tech- nology that allows more intensive harvesting.
In some cases there is a risk that the yield of the wetland exceeds its primary production;
the wetland system loses resilience and the stocks are depleted. In other cases, such as the
harvesting of biomass from fenland and subse- quent fuel or feedstock production, ecosystems
integrity can be maintained and enhanced.
3. Direct exploiters dredge the sediments in the wetland, or exploit mineral resources, peat,
clay and sand without due concern for the ‘health’ of the wetlands.
4. Agricultural producers drain and convert wet- lands to agricultural land, since, at least in the
short to medium run, the soil is fertile, nutri- ents are plentiful and water is freely available.
5. Water abstractors use wetlands as sources of drinking water, agricultural irrigation, flow
augmentation, etc. These practices may result in a wetland suffering a fall in its water table
and consequent quality degradation, or in the diversion of ‘polluted’ water into the wetland.
6. Human settlements close to wetlands. Many wetlands are located in the transition zone
from land to water, and may thus constitute convenient areas for the expansion of human
settlements and their infrastructure; a paradox is often evident as the very presence of water is
a
valuable amenity
that needs
to be
safeguarded.
7. Indirect users benefit from indirect wetland services such as storm abatement, flood miti-
gation, hydrological stabilisation and water purification to individuals and communities
across large catchment areas; because of the extensive spatial provision of such services
many recipients will be unaware of their origin.
8. Nature conser6ation and amenity groups com- bine nature conservation objectives with an
enjoyment of the presence of plant and animal species. This aesthetic value of wetlands is
often mixed with recreation usage values.
9. Nonusers may, geographical distance notwith- standing, attribute nonuse value to wetlands,
possibly due to their recognition of intrinsic value in wetlands.
Clearly not all stakeholder interests are mutu- ally compatible and the potential for value confl-
ict is high. Policy makers are therefore required to undertake complex trade-off procedures and
would benefit from the provision of integrated economic data and analysis.
5. Monetary valuation techniques and cost-benefit analysis
